This invention relates to a striker embodying an improved construction and relationship of parts for attachment to the sill of a railway vehicle and for more efficiently transferring pull and buff forces between a coupler and a railway vehicle. More particularly, the present invention relates to such a striker having an endless rib projecting outwardly from each side wall to reinforce a key slot in the side wall and present a continuous surface for welding the striker to the sill of a railway vehicle. The present invention also provides a striker having inwardly-displaced side wall sections above and below key-slot openings in the side walls to: (a) inwardly shift the neutral axes of the wall sections for loads imposed on front draft lugs of the striker: and preferably (b) form welding sites at high-strength wall sections for a major transfer of loads on the striker.
Conventional striker castings for E-type couplers have a discontinuous rib protruding from the lateral side walls of the striker casting. The key-slot reinforcement rib has terminal end faces directed rearwardly of the casting and spaced from draft lugs which are flat surfaces orientated vertically when the striker is operatively arranged in the sill of a railway vehicle. The key-slot reinforcement ribs protrude from the side walls of the striker and form extensions to part of horizontal key-slot openings in the side walls which align with the key-slot opening in the shank of a railway coupler. A yoke engaged with the draft gear at the rear of the striker has a nose portion that extends forwardly along the side edges of the coupler shank within a pocket opening of the striker. The nose portion of the yoke has key slots to register with the key slots in the coupler shank and the side walls of the striker so that a key can be passed horizontally through all of the key slots. The key, usually identified as a draft key, is pulled forward by the coupler and seats against the forward ends of the key slots in the yoke and slides within the striker key slot in the pull-mode of operation. However, before the draft key slides along the striker key slot, the pull force on the coupler is transmitted by the key in its shank to the yoke which, in turn, imposes the pull load on a draft gear which is transmitted through follower blocks to the front draft lugs of the striker. The striker is welded to the sill of the railway vehicle to transmit the pull force to the railway vehicle.
Buff forces on the coupler first push the coupler shank rearwardly in the striker so that the butt end of the coupler shank seats against the draft gear. The initial buff forces compress the draft gear against the rear draft lugs. The rear lugs transmit the buff forces to the structure of the car underframe. As the draft gear compresses, the coupler key slot contacts and slides the draft key rearwardly along the striker key slot. The draft gear also serves to reduce tremendous load shocks and prevents rigorous pounding as the draft loads shift between the rear and striker draft lugs. The cyclic loading on the striker draft lugs by the draft gear in the past caused the welded connection between the striker and the sill to fail. The present invention is based on the discovery that the design of the striker casting contributed to weld failures because only a discontinuous weld bead could be formed. The striker design required termination of weld metal at the rear part of the striker where projecting key-slot ribs terminate.
Another deficiency of known strikers relates to draft lugs at the rear of the casting usually called "front draft lugs". The vertical side walls of known striker castings are planar, parallel wall sections having a right-angled, cantilevered web which forms the draft lugs. Usually, inwardly-projecting ribs are formed on the rear inside part of the side wall, but they fail to sufficiently strengthen the walls against an inward bowing due to forces acting on the draft lugs during operation of the coupler. This imposes an undue stress on the striker casting at the rear portion closely adjacent the draft lugs. Such stress must be resisted by the weld metal that is discontinuous at this area to maintain the integrity of the attachment with the sill of the railway vehicle. At the terminal end portions of the weld beads, the weld metal tears away from the striker casting and/or sill, allowing side walls of the striker casting greater freedom to flex and ultimately a complete fatigue or brittle fracture weld failure.